Hong Kong began culling thousands of chickens Wednesday after the deadly H7N9 virus was discovered in poultry imported from China, days after the city raised alert levels when a woman was hospitalised with the disease.

A new research suggests that a dangerous strain of avian influenza, H7N9, that`s causing severe illness and deaths in China may be inhabiting a small fraction of its potential range and appears at risk of spreading to other suitable areas of India, Bangladesh, Vietnam, Indonesia and the Philippines.